File bugs here for issues related to non-conforming behaviors in any of JavaScript's standard class constructors, methods exposed on instances through the prototype chain, and so on. (Examples: String.prototype.charAt doesn't work on non-String objects, the Object constructor doesn't work correctly when passed document.all, etc.)

If the relevant functionality has a more-precise component, bugs within it should be filed there (e.g. Intl.NumberFormat bugs should be filed in the JavaScript: Internationalization API component).

Read bug 957086 comment 47:
1) Can you file a followup bug to get JSAPI to expose a version of JS_IsIdentifier that takes chars+length and then nix the need for a cx in IDB's CreateObjectStore and CreateIndex code? That seems all the cx is used for there.

Basically, out situation is that we have an XPCOM string that we want to check for being a JS identifier. Right now we have to go and create a JSString from it to do that, which seems a bit silly.
Jason, if you're OK with the basic idea, I'll just do this.